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3PAR developing united federation of clusters

Boldly going where no SAN has gone before

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3PAR is actively developing technology needed to federate its InServ clustered storage arrays together and provide a single pool of resources across the federation.

3PAR believes that there is a practical limit to the scaling on the number of nodes in a cluster, due to the risk of a node failure taking the entire cluster down. However, the needs of cloud-type computing will inevitably mean total capacity has to scale beyond the limits of an InServ cluster. The way to do this, 3PAR thinks, is to federate its clusters together, but retain InServ manageability to prevent sysadmins having to get up close and personal with the federated cluster's operating controls.

Craig Nunes, 3PARS's marketing chief, said: "We want to get away from folks having to manage capacity in a box. So you need a fluid provisioning capability [with a] peer relationship between arrays in a metro area. Each understands where SATA capacity is, where Fibre Channel capacity is, etc [across the federation]. Folks get storage from a virtual pool... what we do in an array it is possible to do across arrays [clusters] in a metro area."

What sort of distances are we talking about? "Fibre Channel distances; miles apart," meaning a large campus and not long distance.

If users in such a federation were to move, then you could ensure that resources followed them.

Nunes doesn't favour the term "super-cluster": "No. We're actively investing in ways to hide and maybe eliminate the idea of a cluster for storage guy." Storage people might be wary of the complexity implied with a super-cluster, complexity they would have to deal with: "Federation is a less scary way to think about it."

Cluster-level failover across the federated nodes would be a desirable feature.

3PAR thinks federation is entirely practical. Nunes said: "It's a strategic concept for us... and a number of components are in active development today... We're going to be making an upcoming announcement about this." Expect something before the end of November."

3PAR SNW news

At SNW in Frankfurt, 3PAR announced improvements to its InServ product. A Persistent Cache facility will share out the duties of a failed cache in a 4-node or greater InServ array and so avoid the degradation of cache function currently seen with a cache failure in a node. There is a new disaster recovery facility with synchronous replication of changes to one InServ array to another local array and scheduled asynchronous replication to a remote InServ array.

If the primary site goes down then a replacement site comes into play, using the asynchronously replicated data plus the synchronously replicated data since the last asynchronous replication.

Lastly 3PAR has announced RAID MP, a faster RAID 6 technology that is only 15 per cent slower than RAID 10 in terms of performance but equivalent to RAID 5 (3 + 1) in terms of capacity. RAID MP uses 3PAR's third generation ASIC to achieve its speed and 3PAR says RAID re-build is "four times faster than traditional rebuilds." It supports double parity and will be able to support triple and quad parity in the future. ®